Critical Spring Temperatures

The critical control temperatures for apple blossom buds are given in the table below.

  • Old standard temperature is the lowest temperature that can be endured for 30 minutes without drainage.
  • This table also shows the temperature that will kill 10% and 90% of normal fruit buds.

Critical spring temperatures for apple blossom buds

Apple Stages

Critical Control Temperatures

Silver tip

silver_tip
  • Old temp1: 16
  • 10% kill2: 15
  • 90% kill2: 2

Green tip

green_tip
  • Old temp: 16
  • 10% kill: 18
  • 90% kill: 10

Half-inch green

1-2_green
  • Old temp: 22
  • 10% kill: 23
  • 90% kill: 15

Tight cluster

tight_cluster
  • Old temp: 27
  • 10% kill: 27
  • 90% kill: 21

Pink

pink
  • Old temp: 28
  • 10% kill: 28
  • 90% kill: 25

King bloom

king_bloom
  • Old temp: 28
  • 10% kill: 28
  • 90% kill: 25

Full bloom

full_bloom
  • Old temp: 29
  • 10% kill: 28
  • 90% kill: 25

Post bloom

petal_fall
  • Old temp: 29
  • 10% kill: 28
  • 90% kill: 25

1 Critical temperatures as previously published in WSUEM 1616.
2 Average temperatures found by research at the WSU Research and Extension Center, Prosser, to result in 10% and 90% bud kill.

These numbers were taken from WSU Extension bulletins. Portions of these bulletins are posted at Greg Lang’s Fruit Bud Hardiness page at the MSU Horticulture Department.

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